[Khosrau I (d. 579), king of Persia, seated on throne, directing Burzuwayh, the sage, to go to India to procure the Kalilah Wa Dimnah ("Book of Wisdom")]

Iran, or Persia, is home to one of the world's oldest major civilizations, with first known urban settlements dating back to 7000 BC. Georg Wilhelm Friedrich Hegel names the Persians as the first Historical People. The Persian civilization begins in the Iron Age. The First Persian Empire was the only civilization in all of history to connect over 40% of the global population, accounting for approximately 49.4 million of the world's 112.4 million people in around 480 BC. They were succeeded by the Seleucid, Parthian and Sasanian Empires, who successively governed Iran for almost 1000 years. The Muslim conquest of Persia (633–656) ended the Sasanian Empire of classical antiquity and was a turning point in Iranian history. Islamization of Iran took place during the eighth to tenth centuries and led to the eventual decline of Zoroastrianism in Iran as well as many of its dependencies. The achievements of the previous Persian civilizations were to a great extent absorbed by the new Islamic civilization. Persia's arch-rival was the Roman Empire and its successor, the Byzantine Empire.